Containers are commonly used in the food and beverage industry to hold and store the food or beverage. In the commercial distribution of many food products, including many beverages, the products are packaged in cartons, cans, bottles, Tetra Pak® packages, or wax carton packs of varying sizes. In addition, the containers are usually manufactured from many different types of materials, such as metals, glasses, ceramics, papers, treated papers, waxed papers, polymeric materials, composites, and layered structures. The polymeric material typically includes polyolefins (e.g., polyethylene, polypropylene, polystyrene, and mixtures thereof), polyesters (e.g., polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and mixtures thereof), polyamides, and/or polycarbonates.
In most packaging operations, the containers are moved along conveying systems, usually in an upright position, with the opening of the container facing vertically up or down. The containers are moved from station to station, where various operations, such as filling, capping, labeling, sealing, and the like, are performed. Lubricants are often used in conveying systems for containers to ensure the appropriate movement of containers on the conveyor. Specifically, the lubricating solutions are often used on conveying systems during the filling of the containers, for example, with beverages.
There are a number of different properties that are desirable for beverage lubricant compositions. For example, the lubricant composition should provide an acceptable level of lubricity for the system. It is also desirable that the lubricant composition have a viscosity that allows it to be applied by conventional pumping and/or application apparatus (e.g., spraying, roll coating, or wet bed coating). In addition, in the beverage industry, there is a high demand for conveyor lubricant compositions that are beverage compatible. Beverage compatibility refers to the lubricant composition not forming solid deposits when it accidentally contacts spilled beverages on the conveyor system. This property is important since the formation of deposits on the conveyor system can change the lubricity of the system and could require shut-down of the equipment to facilitate cleaning.
Carbonated beverages usually contain ingredients with anionic charges, such as colors and flavors, which are held in solution through emulsification. Given this generally negative charge, the cationic constituents of a synthetic lubricant, such as quaternary ammonium salts, amines, and ether amines, may react with the beverage to form precipitates. The precipitates accumulate on conveyors, housing, and floors as a tenacious soil, and may cause a halt in production to facilitate cleaning.
When the lubricant composition is for use on PET bottle lines, acceptable compatibility with PET is desired. Currently, containers, including PET bottles, and/or the conveying system are often coated with an aqueous-based lubricant composition to provide lubricity to the container so that it can more easily travel down a conveyor system. Many currently used aqueous-based lubricant compositions are less than desirable because they are incompatible with many beverage containers, such as PET and other polyalkylene terephthalate containers, and may lead to stress cracking and rupture of the PET bottles.
Many of the known beverage lubricant compositions, upon cooling to about 0° C., form a precipitate in the container. The precipitate usually requires a significant amount of heating and/or agitation to redissolve the precipitate into solution. As such, the presence of a precipitate in the beverage lubricant compositions is undesirable to consumers.
Lubricant compositions having quaternary ammonium agent and phosphate esters are known to have good lubricity. However, mixing of certain ratios of the quaternary ammonium compound and soft drink spillage usually contribute to soiling of the beverage.
Lubricant compositions having fatty acids are known to have good lubricity, especially for metal surface lubrication. However, fatty acids generally need to be neutralized in order to have a good solubility in water. The use of sodium or potassium hydroxide as the neutralizing agent, in fatty acid containing lubricants, has been found to increase the alkalinity of the lubricant composition, and to thus contribute and promote the stress cracking in PET containers.
Additionally, many compositions currently used in the industrial and institutional industry do not exhibit stability over broad temperature ranges typically encountered with the shipping and storage of these compositions. Such compositions include, e.g., compositions useful in the cleaning, rinsing, lubricating, and antistatic fields. These compositions are typically transported and stored in unheated transportation vehicles (e.g., trucks) and stored in unheated units (e.g., sheds or warehouses). The lack of stability of these compositions can often be seen as a solidification (i.e., precipitation) of one or more components in the composition. This solidification can result, e.g., in a loss of homogeneity in pumping the composition, which can cause nozzle plugging. Removing and cleaning out plugged nozzels is time consuming, as well as financially expensive. Removing and cleaning out plugged nozzels can also effect product performance.
Currently, there is a need for a surfactant composition (e.g., lubricant composition) exhibiting stability as a solution or a dispersion at a temperature of about 0° C. to about 8° C. Such surfactant composition (e.g., lubricant composition) should exhibit beverage compatibility. In addition, the surfactant composition (e.g., lubricant composition) should exhibit compatibility with PET.